package com.dragon.java.tcpchat;

import java.io.IOException;
import java.net.Socket;
import java.net.UnknownHostException;

/**
 * 客户端
 * 
 * @author Auser
 * 
 */
public class Client {
  public static void main(String args[]) throws UnknownHostException,
      IOException {
    Socket client = new Socket("192.168.1.188", 10000);

    // 穿件发送信息的线程
    new ClientSend(client).start();
    // 创建接收信息的线程
    new ClientReceive(client).start();
　　　　　// 因为要实现聊天功能，而不是只发送一次信息，所以输出流和客户端都不能关闭。
    // client.shutdownOutput();
    // client.close();

  }
}

package com.dragon.java.tcpchat;

import java.io.IOException;
import java.io.PrintStream;
import java.net.Socket;
import java.util.Scanner;

/**
 * 客户端向服务端发送信息的线程
 * 
 * @author Auser
 * 
 */
public class ClientSend extends Thread {
  private Scanner scanner;
  private Socket socket;

  public ClientSend(Socket socket) {
    this.socket = socket;
  }

  @Override
  public void run() {
    scanner = new Scanner(System.in);

    try {
      PrintStream ps = new PrintStream(socket.getOutputStream());
      String line = "";
      // 阻塞式发送信息
      while ((line = scanner.nextLine()) != null) {
        ps.println(line);
      }
    } catch (IOException e) {
      e.printStackTrace();
    }
  }
}

package com.dragon.java.tcpchat;

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.net.Socket;

/**
 * 客户端接收信息的线程
 * 
 * @author Auser
 * 
 */
public class ClientReceive extends Thread {
  private Socket socket;

  public ClientReceive(Socket socket) {
    this.socket = socket;
  }

  @Override
  public void run() {
    try {
      BufferedReader br = new BufferedReader(new InputStreamReader(
          socket.getInputStream()));
      // 按行接收信息
      String line = "";
      while ((line = br.readLine()) != null) {
        System.out.println(line);
      }
    } catch (Exception e) {
      e.printStackTrace();
    }
  }

}

package com.dragon.java.tcpchat;

import java.io.IOException;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.ArrayList;
import java.util.List;

/**
 * 服务器
 * 
 * @author Auser
 * 
 */
public class Server {
  public static void main(String[] args) throws IOException,
      InterruptedException {
    List<Socket> list = new ArrayList<>();

    // 创建服务器端的套接字
    ServerSocket server = new ServerSocket(10000);

    while (true) {
      // 接收客户端的阻塞方法
      Socket socket = server.accept();
      // 设计到多个线程可能会对集合进行增删的操作，要进行同步的处理
      synchronized (list) {
        list.add(socket);
      }
      // 启动一个新的线程去处理这个客户端的交流
      new HandleSocket(socket, list).start();
    }
　　　　 // 因为不知道客户端什么时候发送信息，所以服务端要一直开启不能关闭。
  }
}

package com.dragon.java.tcpchat;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintStream;
import java.net.InetAddress;
import java.net.Socket;
import java.util.List;

/**
 * 处理每个(单个)连接到服务器的客户端的线程
 * 
 * @author Auser
 * 
 */
public class HandleSocket extends Thread {

  private Socket socket;
  private List<Socket> list;

  /**
   * 构造方法
   * 
   * @param socket
   *      当前连接的客户端
   * @param list
   *      存储已连接客户端的集合
   */
  public HandleSocket(Socket socket, List<Socket> list) {
    this.socket = socket;
    this.list = list;
  }

  /**
   * 线程run方法
   */
  @Override
  public void run() {
    InetAddress address = socket.getInetAddress(); // 获取连接到服务器的这的客户端的地址
    String ip = address.getHostAddress();
    System.out.println(ip + "上线了！");
    if (ip.equals("192.168.1.117")) {
      synchronized (list) {
        sendToAll(ip + "由于违规操作，已被拉入黑名单！");
        list.remove(socket);
      }
      return;
    }

    try {
      BufferedReader br = new BufferedReader(new InputStreamReader(
          socket.getInputStream(), "gbk"));

      String line = "";
      while ((line = br.readLine()) != null) {
        String msg = ip + ":" + line;
        System.out.println(msg); // 输出到服务器端的控制台
        // 把这个客户端说的话，发给其他所有的客户端
        sendToAll(msg);
      }

    } catch (IOException e) {
      // e.printStackTrace();
      System.out.println(ip + "下线了！");
      synchronized (list) {
        list.remove(socket);
      }
    }
  }

  /**
   * 把信息发送给所有的客户端，去除当前socket
   * 
   * @param msg
   *      发送的信息
   */
  private void sendToAll(String msg) {
    synchronized (list) {
      for (Socket s : list) {
        if (s != socket) {
          try {
            PrintStream ps = new PrintStream(s.getOutputStream());
            ps.println();
          } catch (IOException e) {
            e.printStackTrace();
          }
        }
      }
    }
  }

}